See https://turbotax.intuit.com/tax-tips/amend-return/how-to-file-an-amended-return-with-the-irs/L6kO691J8
and
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-already-filed/L4VjJ9BA2_US_en_US
And...you will have to mail your amended 2021 return. Use a mailing service that will track it and give you confirmation that it is received because you will have a long wait (four to six months-- or more) for it to be processed.
You can watch for information here:
https://www.irs.gov/Filing/Individuals/Amended-Returns-(Form-1040-X)/Wheres-My-Amended-Return-1
Always have a saved copy of your original return before you do any amend. Once you start amend you overwrite the original.